By labeling sperm surfaces with ferritin-conjugates of plant lectins, we will study how the glycoprotein coat on the plasma membrane changes during capacitation of hamster and guinea pig spermatozoa. This study will be conducted in parallel with isolation and characterization of the surface-coating substances utilizing 125I-labeling technique. The energy output by spermatozoa activated in vivo and that by spermatozoa in the process of passage through the zonz pellucida will be determined by cinematographic analysis and mathematical computation. The possible importance of the lipid moiety of the sperm plasma membrane in the ability of spermatozoa to fuse with eggs will be studied by treating acrosome-reacted spermatozoa with a variety of enzymes and membrane-lipid-active substances. Intracellular distribution of actin in the mammalian sperm heads will be studied by utilizing anti-actin antibody. Whether sperm actin changes its form (granular to filament) during capacitation of spermatozoa will be studied. Preliminary study will be conducted to characterize sperm actin by biochemical means.